US2734552A - yonash - Google Patents

Description

Feb. 14, 1956 Filed Nov. 1, 1952 R. F. YONASH 2,734,552

Fig.

INVENTOR. Robert F. Yonash Attorney Feb. 14. 1956 R. F. YONASH METAL CORRUGATING MACHINE I: Sheets-Sheet 3 Filed Nov. 1, 1952 INVENTOR. Robert F. Yonash Attorney United States Patent METAL CORRUGATING MACHINE Robert F. Yonash, Dallas, Tern, assignor to The Joggler Corporation, Garland, Tex., a corporation of Texas Application November 1, 1952, Serial No. 318,176 12 Claims. (Cl. 153-76) This invention pertains to an apparatus for forming bends in sheets of deformable material, such as sheet metal, and particularly to apparatus especially adapted to form non-parallel corrugations in such sheets.

Corrugated sheet metal is widely used as a structural material because of its light weight and its ability to resist bending transverse to its corrugations. The usual sheet of corrugated metal is corrugated uniformly, that is, the corrugations are of the same depth and spacing over the entire width and length of the sheet. However, for special applications, such as employment in the fabrication of airplane wing sections and fuselage, it is desirable to have sheets of corrugated metal in which the corrugations vary in spacing from one end of the sheet to the other.

The conventional apparatuses which are employed to form corrugations in sheet metal are adapted'to form only sheets having uniform corrugations. Heretofore, sheets in which non-uniform or non-parallel corrugations were required have been formed on conventional press brake machines in which the sheet was deformed, or corrugated, by inserting it into the press brake machine and forming a bend in one direction, removing the sheet from the machine, turning it over, forming another bend in the sheet in the opposite direction, and so on until the proper number of bends had been made in the sheet.

It is an object of this invention to provide an apparatus to facilitate the easy and rapid formation of non-parallel corrugations in the sheet of deformable material.

It is a further object of this invention to provide an apparatus in which a series of corrugations of non-uniform cross-section may be formed in a sheet of deformable material without the necessity for removing the sheet from the apparatus and turning it over between successive corrugations.

It is another object of this invention to provide an ap paratus which is especially adapted to facilitate the forming of non-uniform corrugations in sheets of deformable material, although the apparatus may, if desired, be employed also in forming uniform corrugations.

It is a further object of this invention to provide a sheet metal forming apparatus comprising a pair of horizontal clamping members which are adapted to clamp a sheet of metal therebetween leaving a portion of the metal overhanging, and provided with means for selectively bending said overhanging portion either upwardly or downwardly with respect to the clamping members.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the attached drawings.

Figure l is a front elevation of a preferred embodiment of the metal corrugating apparatus of this invention, showing the parts thereof in the position which they normally the position occupied when the clamping shoes are 2,734,552 Patented Feb. 14, 1 956 clamped to a sheet of. metal and the upper forming platen has been lowered to bend the overhanging portion of the sheet downwardly.

Figure 4 is a fragmentary sectional view taken along the line 4-4 of Figure 2 to show the manner in which the lower forming platen is reciprocally mounted on the lower frame member.

Figure 5 is a fragmentary sectional view taken on the line 55 of Figure 1 to show the stop means which are provided for limiting the downward and upward reciproeating movements, respectively, of the upper and lower.

forming platens.

Figure 6 is a view taken on the line 6-- 6 of Figure 1, having superimposed thereon a sheet of metal in the position which it would occupy prior to having corrugations formed therein.

Figure 7 is a plan view of a typical corrugated sheet such as might be produced using the apparatus of this invention.

Figure 8 is a section taken on line 8-8 of Figure 7.

Figure 9 is a section taken on line 99 of Figure 7.

From the drawings, and particularly with reference to Figure 1, it will be noted that support columns 1 and 2 having footings 3 and 4, respectively, on the lower ends thereof rest on a suitable foundation, such as concrete floor 5. Preferably, footings 3 and 4 are anchored to floor 5 in any suitable manner, as bolts not shown.

Support columns 1 and 2 are preferably cast integral with their respective footings 3 and 4, webs 6 being provided to insure the rigidity and perpendicularity of the,

columns with respect to their footings. Piston rod 7 is rigidly mounted in support column 1 so as to be immovable with respect thereto, and piston rod 8 is similarly mounted in support column 2. Cylinders 9 and 10 are reciprocally mounted on piston rods 7 and 8, respectively. Cylinder 9 is preferably provided with an upper flange 11 to which is secured, by bolts or clamps, not shown, lower flange 12 of hydraulic cylinder 13 into which extends the upper end of piston rod 7, said piston rod having a piston, not shown, mounted on the upper end thereof for coopcrating with said hydraulic cylinder, as will be understood by those familiar with the construction and operation of hydraulic cylinder apparatus. Likewise, a hydraulic cylinder 14 having flange 15 is similarly secured to upper flange 16 of cylinder 10. The upper ends of hydraulic cylinders 13 and 14 are closed by cover plates 17 and 18, respectively.

It will be appreciated that, since piston rods 7 and 8 are rigidly fixed in support columns 1 and 2, respectively, cylinders 9 and 10 may be raised and lowered on piston rods 7 and 8 by the proper introduction and withdrawal of hydraulic fluid under pressure in cylinders 13 and 14.

Since the construction and operation of hydraulic cylinders are so well known, and also since the hydraulic system per se is not within the scope of the present in vention, a detailed discussion of the hydraulic system is not thought to be necessary; and further, the fluid lines connecting the hydraulic cylinders with the source of hydraulic fluid have been eliminated from the drawings in the interest of clarity.

Lower clamping member 19 is supported by and between support columns 1 and 2, being secured to flange 20 of support column 1 and flange 21 of support column 2, as by bolts or screws 22 which are preferably countersunk.

As more clearly shown in Figures 2 and 3, lower clamping member 19 is preferably reinforced by structural support plates 23, 24, and 25 secured to the rear face thereof, as by welding.

Also, as more clearly shown in Figures 2 and 3, lower clamping member 19 has secured to the upper edge thereof, as by screws or bolts not shown, a clamping shoe 26,

greases 3 The upper and forward edge of clamping shoe 26 comprises a forming lip 27 which may either be integral with clamping shoe 26 or secured thereto by any suitable means such as screws, not shown. 7

An upper clamping member 28 is supported by and between cylinders 9 and 10, being secu ied to flange 29 of cylinder 9 and flange 30 of cylinder 10, as by bolts or screws 31, which are preferably countersunk. Upper clamping member 28 is preferably reinforced by structural support plates 32, 33, and 34 secured 'tojthe rea'rjface thereof, as by welding.

As more clearly shown in Figures 2 and 3, upper clamping member 28 has secured to the lower'edge thereof, as by screws not shown, an upper clamping $1 which is substantially identical to lower clamping shoe 26 secured to the upper edge of lower clamping mernber '19, as hereinabove described.

The lower and forward edge of upper elamping shoe 35 comprises a forming lip 36 which may he formed integraltherewith or otherwise suitably secured thereto, as by screws not shown.

It will be appreciated that the upper face offorrning lip 27 and the lower face of forming lip36 are adapted to rigidly clamp a sheet of metal therebetween upon the lowering of upper clamping member 28 with respect to lower clamping member 19, as will be more'fully explained hereinafter.

A lower forming platen 37 is mountedon -the frontface of lower clamping member 19 so ,as to be vertically ,reciprocable with respect thereto. To this end, a plurality of T-shaped bars 38 secured, as by countersunk screws 39, to the rear face of lower forming platen 3 7 fareadapted to ride in the 'T-s1ots formed between pairs of L-shaped blocks 40 secured, as .by countersunk screws 41,10 the front 'face of .lower clamping member 19. For a clearer understanding of the mounting of lower forming platen 37 onlower clamping member .19, as explained above, special reference is made to the detail drawing of Figure 4. Upper forming platen 42 is similarly reciprocably mounted on upper clamping member 23 by means of T-shaped blocks 43 secured to the rear face of said forming platen, said T-shaped blocks being adapted to reciprocate within the T-slots formed between pairs of L-shaped members 44 secured to the front face of upper frame member 28.

'As more-clearlyshown in Figures 2, 3,-and 5, the upper edge of lower forming platen 37 isprovided with a forming-lip 35 which may bejmade integral with lower forming platen 3.7, but which is preferably removably secured thereto, asby screws not shown. Likewise, theflower edge of upper forming platen 42 is provided with 'forrning'lip 46 which maybe integral, but which'is preferably removablysecured thereto.

Lower forming platen 37 is adaptedto he raised with respect to'lower clamping member19 bythe action of a plurality -'of rams '47 comprising the piston rods of hydraulic cylinders '48-'which are secured, as'by clamps 49 and screws '50,-to the front "face of lower clamping member$I-9;-and isadaptedto be lowered with respect thereto by hydrauliccylinders Slhaving piston rods 52 secured to the lower edge iof forming platen 37, as .bybeing threaded thereinto, cylinder 51 being fixedly secured to lowerifrarne member 192118 :by bolts 53 passing through lugs 54 which are preferably formed integral with cylin ,ders 51.

,Likewise, upper forrning;platen-42 is adapted to be lowered and raised, by the action of rams-55. of hydraulic cylinders 56, and by the,piston.rods-57 of.hydraulic cylinders 58, respectively.

In the interest of clarity, thefiuid .linesrconnecting the several hydraulic cylinders described above with the source of hydraulic fluid have been eliminated fromthe drawings. Furthermore, since the construction and operation of hydrauliccylinders.area matter of widespread common knowledge, well withinflthepurviewnof those 4 skilled in the art, no detailed description of this portion of the apparatus is thought to be necessary.

Wear pads 59 are secured to the lower and upper edges, respectively, of lower and upper forming platens 37 and 42 at the points of contact by rams 49 and 55, respectively, in order to prevent undue wear on the forming platens themselves.

As more clearly shown in Figures 2 and 3, a table 60, supported, as for instance on frames 61, is provided as a means for supporting a sheet of metal at the level to he clamped between clamping shoes 26 and 35.

As more clearly shown in Figure 6, templates 62, having guide holes 63 punched therein are secured to thetop of table 60 to provide means for controlling the extent to which a sheet of metal being corrugated, as for instance sheet 64, is to be advanced between each operation of the corrugating apparatus, as will be discussed in more detail hereinafter.

A pair of clamps 65, each having means, as for instance thumb screw 66, for securing it to the rear edge of sheet 64 and also having a pin 67 which is of such diameter as to fit snugly in holes 63, are secured to the rear edge of sheet'64, being in such position that each may cooperate with the holes 63 in one of the templates 6 2. It be understood that after each bending operation performed on the sheet, as hereinafter described, pins 67 of clamps 65 are to be lifted from one set of holes 63 and advanced to the next forward set of such holes. Obviously, by varying the spacing of the holes 63 in one of the templates 62 with respect to the holes in the other of said templates, sheet 64 maybe skewed as it is advanced for successive bending operations, whereby to facilitate the making of non-parallel'hends-in the sheet, and the forming of a sheet such as, for instance, the sheet shown in Figures '7, 8, and-9. Y

The operation of the apparatus as described above is thought to be reasonably self-evident; however, a brief description of the operation maybe in order.

With-the respective components of-the apparatus in the positions shown in Figures '1 and 2, a sheet of metal, not shown in Figures 1 and '2, is placed fiat on table 6!) with a portion thereof overhanging the forward edge of'forming lip 27 of lower clamping shoe 26. By operation of hydraulic cylinders 13 and 14, as will be understood by those skilled in the art, upper clamping member -28 is lowered with respect-to 'lowerclamping member-19-thus resulting in the clamping of the sheet between the forming lips '27 and ' 360f clamping shoes 26 and 35, respectively, as shown ;in Figure "3. The overhanging portion of the sheet may then be bent-downwardly by 'loweringforming platen A2 sufiicientlytomovethe loweredge (if-forming lip 46 below the clamping space between forming-lips 27 and. 3 6, as shown in'Figure 3; or-may be bent upwardly by raising lower forming platen :37 sufliciently to raise theuppertedge offorming'lip 5&5 .above the level of said clamping ispace. It will .be understood that the term clamping space .as used herein refers to the space between forming j'liPS'127 and 3.6 whensaid lips are in aposition to elamp a sheettherehetween.

Thus, .by ;clamping a sheet between clamping shoes -26 and .35, twith -a' portion of .said sheet overhanging the for- ;ward-edgesof "forming lips 27 and =36,lowe ring forming platen 142, or-raising forming platen37, to'bend'the sheet, returning the forming platens to their normal positions, releasing-the sheet by raising clamping shoe-35, advancing the-sheet by the desired, amount and repeating the ing, bending, and releasing operations, a sheet maybe defoimed by aseries of straight-line bends in anydesired spacing or angular relationship with respect to eachother, depending upon theextent to whichthe sheet isadvanced between successive bending -;operat ions, and depending upon whether the sheet is moved straight forward or skewed between successive-bending operations.

It l b t r regiate th t t e h riz n a :saaciash tween the ow r -e ttomisali s 1 an a an the rear faces of forming lips 45 and 46 is such as to accommodate the thickness of the sheet being corrugated without unduly pinching the same. In general, this spacing is substantially equal to the thickness of the sheet being corrugated. Also, it will be appreciated by those skilled in the art, that a sheet of metal of thick crosssection may not be bent as sharply as a thinner sheet without danger of rupturing the sheet at the bend. Therefore, it will be understood that the radius of curvature of forming lips 27 and 36, which may be satisfactory when forming thin sheets, will be unsatisfactory for forming sheets of greater thickness. Accordingly, it will be understood that forming lips 27, 36, 45, and 46 may be replaced by similar forming lips of slightly different dimensions and shapes, said lips being changed as necessary, depending upon the thickness of the particular sheets being formed. Alternatively, if the forming lips are formed integral with the respective clamping shoes and forming platens, the shoes and platens may be changed according to the thickness of the sheets being formed.

In order to stop the downward movement of upper; forming platen 42 after movement of forming lip 46 sufficient to make the desired bend in the overhanging portion of a sheet clamped between clamping shoes 26 and 35, there are provided a plurality of stop blocks 68 secured to the rear face of upper forming platen 42, as by screws or bolts 69, and adapted to cooperate with stop anvils 70 provided on the upper surface of upper clamping shoe 35. As more clearly shown in Figure 5, the lower end of a stopbolt 71, which passes through stop block 68, is adapted to strike the upper face of anvil 70 whereby to restrain further downward movement of upper forming platen 42. Stop bolt 71 is preferably threaded through stop block 68 in order that it may be raised and lowered, as desired, to effect stopping of forming platen 42 at the desired level. Also, it will be appreciated that the horizontal alignment of the forming platen 42 in its lower stopping position may be controlled by relative adjustment of the stop bolts 71 of the several stop blocks 68. Similar stop blocks 72, stop bolts 73, and stop anvils 74 are provided for controlling the extent of upward travel of lower forming platen 37.

Figures 7, 8, and 9 represent a sheet 75 such as might be formed on the apparatus of the present invention, said sheet being formed with non-parallel corrugations of uniform height. Thus, with special reference being made to Figures 8 and 9, it will be noted that the corrugations of sheet 75 are more closely spaced at the right end than at the left end as shown in Figure 7. It should be noted that due to the radius of curvature of the forming lips, around which the bends 76 in sheet 75 were made, said bends are in the form of gentle curves rather than sharp breaks. Furthermore, it should be explained that, where as the corrugating machine herein described is adapted to make right angle bends, the resiliency of most sheet metals provides sufiicient spring-back to cause the bends in the sheet to be something less than 90 when the pressure of the forming and clamping lips is released. Thus, as more clearly shown in Figures 8 and 9, the risers 77 of the finished sheet 75 make angles of greater than 90 with the top and bottom lands 78 and 79, respectively.

While there has been shown and described a preferred embodiment of the apparatus of this invention, it will be understood that many changes and alterations may be made thereto without departing from the scope of the invention. Accordingly, this invention is not to be considered as limited to the specific embodiment described but rather is limited only in accordance with the appended claims.

I claim:

1. An apparatus for forming bends in a sheet of deformable material comprising a lower clamping member, an upper clamping member, a lower clamping shoe on the upper edge of said lower clamping member, an upper clamping shoe on the lower edge of said upper clamping member and having its forward edge in substantially vertical alignment with the forward edge of said lower clamping shoe, said clamping shoes being parallel with each other and forming therebetween a clamping space adapted to receive said sheet of deformable material, means for selectively moving one of said shoes and its associated clamping member away from the other of said shoes whereby said sheet of material may be moved freely through said clamping space, and toward the other of said shoes whereby to clamp said sheet in said clamping space, a first forming platen reciprocably mounted on said lower clamping member and normally positioned below and for wardly of said clamping space, a second forming platen reciprocably mounted on said upper clamping member and normally positioned above and forwardly of said clamping space, means for selectively raising said first forming platen sufficiently to move the upper edge thereof above the level of said clamping space and for lowering said second forming platen sufficiently to move its lower edge below the level of said clamping space, whereby a projecting portion of said sheet overhanging the forward edges of said clamping shoes may be selectively bent upwardly about the forward edge of said upper clamping shoe by said first platen or downwardly about the forward edge of said lower clamping shoe by said second platen, and means for returning said forming platens to their respective normal positions. 1

2. The apparatus according to claim 1 wherein the lower clamping shoe is stationary and the upper clamping shoe and its associated clamping member are vertically movable with respect thereto.

3. An apparatus for forming bends in a sheet of deformable material comprising a lower clamping member, an upper clamping member, a lower clamping shoe on the upper edge of said lower clamping member, an upper clamping shoe on the lower edge of said upper clamping member and having its forward edge in substantially vertical alignment with the forward edge of said lower clamping shoe, said clamping shoes being parallel with each other and forming therebetween a clamping space adapted to receive said sheet of deformable material, means for selectively moving one of said shoes and its associated clamping member away from the other of said shoes whereby said sheet of material may be selectively moved freely through said clamping space, and toward the other of said shoes whereby to clamp said sheet in said clamping space, a first forming platen, having a forming lip on the upper edge thereof, reciprocably mounted on said lower clamping member and normally positioned below and forwardly of said clamping space, a second forming platen, having a forming lip on the lower edge thereof, reciprocably mounted on said upper clamping member and normally positioned above and forwardly of said clamping space, means for selectively raising said first forming platen sufficiently to move the top edge of the forming lip thereof above the level of said clamping space and for lowering said second forming platen sufficiently to move the lower edge of the forming lip thereof below the level of said clamping space, whereby a projecting portion of said sheet overhanging the forward edges of said clamping shoes may be selectively bent upwardly about the forward edge of said upper clamping shoe by said first platen or downwardly about the forward edge of said lower clamping shoe by said second'platen, and means for returning said forming platens to their respective normal positions.

4. The apparatus according to claim 3 wherein the a lower clamping shoe is stationary and the upper clamping shoe and its associated clamping member are vertically movable with respect thereto.

5. In a bending machine of the type wherein a sheet of deformable material is adapted to be held rigidly in the clamping space formed between an upper clamping shoe on the lower edge of an upper clamping member and a lower clamping shoe on the upper edge of a lower clamparagera ing member, the forward edges of said shoes being in s b: stantially vertical ialignmentand a portion of said sheet projecting forwardly beyond said forward edges, and at least one of. said clamping members being movable vertically with respect to the other, the combination therewith ,of a first forming platen reciprocably mounted on said lower clamping member and normally positioned below and forwardly of said clamping space, a second forming platen reciprocably mounted on said upper clamping member and normally positioned above and forwardly of said clamping space, means for selectively raising said first forming platen sufiiciently to move the upper edge thereof above the level of said clamping space and for lowering said second forming platen sufficiently to move the lower edge thereof below the level of said clamping space, whereby said projecting portion of said sheet may be selectively bent upwardly about the forward edge of said upper clamping shoe by said first platen or downwardly about the forward edge of said lower clamping shoe :by said second platen, and means for returning said forming platens to their respective normal positions.

'6. In a bending machine of the type wherein a sheet of deformable material is adapted to be held rigidly in the clamping space formed between an upper clamping shoe on the lower edge of an upper clamping member and a lower clamping shoe on the upper edge of a lower clamping member, the forward edges of said shoes being in substantially vertical alignment and a portion of said sheet projecting forwardly beyond said forward edges, and at least one of said clamping members being movable vertically with respect to the other, the combination therewith of a first forming platen reciprocably mounted on said lower clamping member and normally positioned below and forwardly of said clamping space, a second forming platen reciprocably mounted on said upper clamping memher and normally positioned above and forwardly of said clamping space, means for selectively raising said first forming platen su-fiicicntlyto move the upper edge thereof above the level of said clamping spaceand for lowering said second forming platen suiliciently to move the lower edge thereof below the level of said clamping space, whereby said projecting portion of said sheet may be selectivelybent upwardly about the forward edge of said upper clamping shoe by said first platen or downwardly about the forward edge ofsaid lower clamping shoe by said second platen, adjustable stop means for limiting the upward travel of said first forming platen, adjustable stop means for limiting the downward travel of said second forming platen, and means for returning said forming platens to their respective normal positions.

-7. In a bending machine of the type wherein a sheet of deformable material is adapted to be held rigidly in the clamping space formed between an upper clamping shoe on the lower edge of an upper clamping member and a lower. clamping shoeon the upper edge of .a lower clamping member, the forward edges of said shoes being in substantially vertical alignment and a portion of said sheet projecting forwardly beyond saidforward edges, the combination therewith of a first forming platen reciprocably mounted on said lower clamping member and normally positioned below and forwardly of said clamping space, a second forming platen reciprocably mounted on said upper clamping memberand normally positioned above and forwardly of @said clamping space, means for selectively raising .said first forming platen sufficiently to move the upper edge thereofabove the :level of .said clamping .space and for lowering said :second forming platen sufficiently .to move the lower edge thereof belowlthe level .of said clamping space, ywherebysaid projecting portion of said sheet may be selectively bent upwardly'about the forward ,edge ,of

- s a id,upper clamping shoe vby said first platen or downyvgrdly about the forward edge of said lower clamping shoe by said second platen, means for returning said forming platens to their respective normalpositions, and-means .fgrselectively ,moY Pg-Qnepf saidclarnping shoes and .-its

18 assoc ted P a n m m e vertical y th ro ed ta hs o her to ef e t se ectiv d m in and eleas n O an h et Wi h n' a d c am in pa Y .8- In a e i mach ne e tim w erei a shee o eform b e ate is a a o b e d i idly i he la pi sp e an e twe an aembhmins $1 9 o t e ow d of an uppe ampi membe and a owe c mpin shoe Q i th ppe e o a l er c m ing m mb he fo ward edg o a d Sho s in in sub ant llv ve t cal a i menta a p o of a d shee projecting forwardly beyond said forward edges, the combination therewith of a first forming platen reciprocably mounted on said lower clamping member andnorrnally positioned below and forwardly. of said clamping space, a second forming platen ecipr v b y mou t n sa d UP.- per clamping member and normally positioned above and forwardly of said clamping space, means for selectively raising said first forming platen sufficiently to move the upper edge thereof above the level of said clamping space and for lowering said second forming platen sufliciently to move the lower edge thereof below the level of said clamping space, whereby said projecting portion of said sheet may be selectively bent upwardly'about the forward edge ,of said upper clamping shoe by said first platen or downwardly about the forward edge of said lower clamping shoe by said second platen, means for returning said forming platens to their respective normal positions", and means for selectively lowering said upper clamping shoe, and its associated clamping member to clamp'said sheet in said clamping space and raising said upper clamping shoe and its associated clamping member'to release said sheet.

9. In a bending machine of the type wherein a sheet of deformable material is adapted to be held rigidly in the clamping space formed between an upper clamping shoe on the lower edge of an upper clamping member and a lower" clamping shoe on the upper edge of a lower clamping member, the forward edges of said shoes being" in substantially vertical alignment and a portion of said sheet projecting forwardly beyond said forward edges, and least one of said clamping members being movable vertically with respect to the other; the combination therewith of a first forming platen, having'a' forming lip on are upper edge thereof, reciprocably mounted on said IoW'er'cIamping memberand normally positioned below and forwardlyof said clamping space, a second forming platen, having a forming lip on the lower edge thereof, recipr'jdcably mounted onsaid upper clamping memberand' normally positioned above and forwardly of "said" clamping space, means for selectively raising said first forming platensufiiciently to move the top edge of the forming lip thereof above the level of said clamping spaceand' for lowering said second forming platen sufficiently to move the lower edge of the forming lip thereof below the levelof said clamping .space, whereby said projecting portion of said sheet may be selectively bent upwardly about the forward edge of said upper clamping shoe by said first platen'or downwardly about theforwardedge of said lower clamping shoe by .sai'd'second platen, and means forreturning said forming platens to their respective normal positions.

10. .In an apparatus for forming bends in a sheetof deformable material comprising a lower clamping memher, an upper clamping member, alower clamping slide on the upper edge ofsaid lower clamping member, an upper clamping shoe on the lowenedge of said upper clamping member and hav'ingits forward edge manss'tantially vertical alignment with the forward edge of said lowrclamping shoe the upper edge ofsaid lower clamping shoe and the lower edge of said upper clamping shoeb'eiiig parallel with each other and forming therebetween a clamping space adapted to receive said sheet of deformable material, means for selectively moving one of s'aid shoes and its associated clamping member away fromthe other of .said shoes whereby said sheet of material niay be .rnoved .freely .through said clamping "space, andtoward the other of said shoes whereby to clamp said sheet in said clamping space, a first forming platen reciprocably mounted on said lower clamping member and normally positioned below and forwardly of said clamping space, a second forming platen reciprocably mounted on said upper clamping member and normally positioned above and forwardly of said clamping space, means for selectively raising said first forming platen sufliciently to move the upper edge thereof above the level of the upper edge of said lower clamping shoe and for lowering said second forming platen sufficiently .to move the lower edge thereof below the level of the lower edge of said upper clamping shoe, whereby a projecting portion of said sheet overhanging the forward edges of said clamping shoes may be selectively bent upwardly about the forward edge of said upper clamping shoe by said first platen or downwardly about the forward edge of said lower clamping shoe by said second platen, and means for returning said forming platens to their respective normal positions.

11. The apparatus according to claim 10 wherein the lower clamping shoe is stationary and the upper clamping shoe and its associated clamping member are vertically movable with respect thereto.

12. In a bending machine of the type wherein a sheet of deformable material is adapted to be held rigidly in the clamping space formed between the lower face of an upper clamping shoe on the lower edge of an upper clamping member and the upper face of a lower clamping shoe on the upper edge of a lower clamping member, the forward edges of said shoes being in substantially vertical alignment and a portion of said sheet projecting forwardly beyond said forward edges, and at least one of said clamping members being movable vertically with respect to the other, the combination therewith of a first forming platen reciprocably mounted on said lower clamping member and normally positioned below and forwardly of said clamping space, a second forming platen reciprocably mounted on said upper clamping member and normally positioned above and forwardly of said clamping space, means for selectively raising said first forming platen sufficiently to move the upper edge thereof above the level of said upper face of said lower clamping shoe and for lowering said second platen sufficiently to move the lower edge thereof below the level of said lower face of said upper clamping shoe, whereby said projecting portion of said sheet may be selectively bent upwardly about the forward edge of said upper clamping shoe or downwardly about the forward edge of said lower clamping shoe, and means for returning said forming platens to their respective normal positions.

References Cited in the file of this patent UNITED STATES PATENTS 375,577 Short -1. Dec. 27, 1887 478,723 Totten July 12, 1892 491,187 Partyka Feb. 7, 1893 507,175 Singer Oct. 24, 1893 533,645 Henry Feb. 5, 1895 1,606,489 Winter Nov. 9, 1929 2,001,273 Greer May 14, 1935 FOREIGN PATENTS 658,766 Germany Apr. 14, 1938

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